LXR linux/tools/perf/util/tsc.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/compiler.h>
   3#include <linux/types.h>
   4
   5#include "tsc.h"
   6
   7u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
   8{
   9        u64 t, quot, rem;
  10
  11        t = ns - tc->time_zero;
  12        quot = t / tc->time_mult;
  13        rem  = t % tc->time_mult;
  14        return (quot << tc->time_shift) +
  15               (rem << tc->time_shift) / tc->time_mult;
  16}
  17
  18u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
  19{
  20        u64 quot, rem;
  21
  22        quot = cyc >> tc->time_shift;
  23        rem  = cyc & (((u64)1 << tc->time_shift) - 1);
  24        return tc->time_zero + quot * tc->time_mult +
  25               ((rem * tc->time_mult) >> tc->time_shift);
  26}
  27
  28u64 __weak rdtsc(void)
  29{
  30        return 0;
  31}
  32